Difference between different oil weights with similar HTHS?

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I have no doubt that had Toyota upped the bulk oil temperature to 150°C+, they could have conclusively 'proved' that the xxW-30s that folks have used for the last 30 years were 'inadequate'.
Of course they probably would conclude that from an engineering viewpoint because the MOFT could be too thin at 150C depending on what the use conditions were. Same reason why oil thicker than xW-30 is typically used for extended track use by car manufacturers.

We all know "use conditions" are a factor, it's even stipulated in many owner's manuals, especially outsude of "CAFE USA".
 
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Regarding your last point, the specs might say 2.6 min HTHS but it's actually tricky to make a commercial oil 'tight' against the minimum spec. The quality of individual batches of base oil, DI & VII can bounce around; not by much but they do. If you aim for 2.6 dead, you might occasionally blend up a batch of oil with a 2.54 cP HTHS which is nominally off-grade (remember blend plants work to FIXED formulations. They are generally never tweaked or trimmed to suit). For this reason, most commercial blenders blend conservatively so HTHS is often higher than the spec permits.

If also worth pointing out that sometimes 'the system' works against you. Euro A3/B3/B4 xxW-30 oils not only have to meet 3.5 min HTHS but also 12.5 cst max KV100 & sometimes the two specs can be mutually exclusive. Unlike in the US, 10W30 engine oils are almost unheard of in Europe because of the impossibility of meeting both specs at the same time. To get to 3.5 min HTHS you sort of need the KV100 to be 12.7 cst whereas a commercially acceptable, blendable 12.3 cst KV100 might only yield an HTHS of 3.35 cP.

I suspect, if you went out & checked, there are probably quite a few xxW-30 A3/B3/B4 oils out there that are like this & technically off-grade for HTHS. However as HTHS is not a widely available test, this anomaly is hardly ever picked up on. It might also part-explain why 5W40s are pushed because these circumvent this issue.

Thanks for the info.

What is your opinion about 0W40 a3/b4 Euro oils and are they popular in Europe? I see more of them here in regular stores. Even though it has high hths, should there be a concern about high amounts of vm (vii) to achieve the wide spread?
 
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Thanks for the info.

What is your opinion about 0W40 a3/b4 Euro oils and are they popular in Europe? I see more of them here in regular stores. Even though it has high hths, should there be a concern about high amounts of vm (vii) to achieve the wide spread?

I don't like wide cross-grade oils like 0W40s & would avoid them like the plague!

When you're formulating oils like this, you can get into a nasty, vicious circle. You can make a 0W40 with a Group III/IV mix but the VII treat is high. The VII messes up your diesel piston cleanliness tests so you add more ashless dispersant to counteract this. This ratchets up your Noack so you move to more PAO & less Group III. Personally I try always to avoid using esters in oils but when PAO goes beyond a certain point, you need some ester to stop the oil drying out the seals. You're probably also now at a point where expensive HSD VII is required for the viscometric/volatility balance to be achieved.

Now what should have been a reasonably priced oil starts to look horribly expensive, all for no genuine gain. I like my relatively cheap, full Group III GF-5 0W20. It's the logical choice.
 

SR5

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If also worth pointing out that sometimes 'the system' works against you. Euro A3/B3/B4 xxW-30 oils not only have to meet 3.5 min HTHS but also 12.5 cst max KV100 & sometimes the two specs can be mutually exclusive. Unlike in the US, 10W30 engine oils are almost unheard of in Europe because of the impossibility of meeting both specs at the same time. To get to 3.5 min HTHS you sort of need the KV100 to be 12.7 cst whereas a commercially acceptable, blendable 12.3 cst KV100 might only yield an HTHS of 3.35 cP.
One of the oils I like is Penrite 10W40 semi-synthetic. It's a Group II & Group III synblend, that's A3/B4 and SN/CF. Nothing special there, but when I looks at the figures, it's different from most of the 10W40 pack out there.

KV100 = 13.5 cSt
Cold Cranking (CCS) at -25C = 6899 cP

Now J300 says a 40 grade oil has a KV100 of 12.5 to 16.3 cSt and 10W has a max cold cranking of 7000 cP at -25C.

So I find the Penrite 10W40 interesting, it's KV100 viscosity is at the lower end and close to a 30 grade, yet the cold cranking is at the upper end and almost a 15W. It's like this oil is not far away from a 15W30 with a heavy add pack (TBN = 11.0 and Zinc = 1220 ppm)

When I rang Penrite on the phone, they confirmed that the oil is a Group II and Group III only blend (it contains no Group I ), and that all Penrite semi-synthetics have a minimum of 20% Group III and possibly more depending on the actual product.
 
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One of the oils I like is Penrite 10W40 semi-synthetic. It's a Group II & Group III synblend, that's A3/B4 and SN/CF. Nothing special there, but when I looks at the figures, it's different from most of the 10W40 pack out there.

KV100 = 13.5 cSt
Cold Cranking (CCS) at -25C = 6899 cP

Now J300 says a 40 grade oil has a KV100 of 12.5 to 16.3 cSt and 10W has a max cold cranking of 7000 cP at -25C.

So I find the Penrite 10W40 interesting, it's KV100 viscosity is at the lower end and close to a 30 grade, yet the cold cranking is at the upper end and almost a 15W. It's like this oil is not far away from a 15W30 with a heavy add pack (TBN = 11.0 and Zinc = 1220 ppm)

When I rang Penrite on the phone, they confirmed that the oil is a Group II and Group III only blend (it contains no Group I ), and that all Penrite semi-synthetics have a minimum of 20% Group III and possibly more depending on the actual product.

Ah this takes me back! Almost every 40 weight test oil I ever made & put on an engine would have a 13.5 cst KV100 & a high CCS (did you know 7,004 cP is technically on-grade!?). The reasons for doing this are simple. Get the VII polymer loading as low as possible to keep the Noack as low as possible & minimise your ashless dispersant treat...all with the objective of minimising cost.

But hey Mr Formulator... isn't that like errr... cheating?? The answer depends on who's asking. If it's Joe Public then very definitely yes... but he has no voice so literally NO ONE cares what he thinks. If it's the OEMs then possibly yes but they know that they'd much rather someone other than them picks up the eye-wateringly exorbitant costs of running programs, so they might conveniently turn a blind eye. If it's the oil companies, it depends which department you talk to. The techies ideally want everything perfect but are always subservient to global purchasing who want just one thing... the lowest cost!

Maybe just ask Penrite to tell you the KO30 shear result for this oil. Don't be surprised if they duck & weave. Generously, I suspect it might be around 12.45 cst... so a pass... sort of...
 
All else being equal, I would select the oil that gives you the most HTHS for the least KV100. This would probably give you the least polymer VII load and better shear stability, lower volatility etc.

It gets difficult when comparing a Group IV based PAO 0W40 to a Group III based 5W30, that are both A3/B4 rated (high HTHS). Easy when it’s a Group III 5W30 A3/B4 to a Group III 5W40 A3/B4, (I go the 5W30).

Look for other OEMs like MB 229.5 which means Noack volatility is below 10%, which is a very good sign.
I just took these photos at Wally World yesterday. Still made in Belgium.

F0CDAB67-0E0B-4650-B771-2E71E086BCF8.jpeg E270E37A-B8BD-47E4-AAC9-67EFF060093D.jpeg 1A1A3515-24C0-4B17-8236-4406E03F995A.jpeg
 
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I don't like wide cross-grade oils like 0W40s & would avoid them like the plague!

When you're formulating oils like this, you can get into a nasty, vicious circle. You can make a 0W40 with a Group III/IV mix but the VII treat is high. The VII messes up your diesel piston cleanliness tests so you add more ashless dispersant to counteract this. This ratchets up your Noack so you move to more PAO & less Group III. Personally I try always to avoid using esters in oils but when PAO goes beyond a certain point, you need some ester to stop the oil drying out the seals. You're probably also now at a point where expensive HSD VII is required for the viscometric/volatility balance to be achieved.

Now what should have been a reasonably priced oil starts to look horribly expensive, all for no genuine gain. I like my relatively cheap, full Group III GF-5 0W20. It's the logical choice.

if I understand you correctly, sounds like 0W40 oil formulation is much more complex and as a result more potential for things to go wrong.

some of the Euro 0W40 oil have bunch of fancy approvals e.g. MB 229.3/229.5, Porsche A40, VW 502 00/503 01/505 00, Fiat, API SN, etc.

Let's say if someone is looking for a high hths or high viscosity oil for towing and not considering the price and complexity, would the long list of approvals and certs make them more legit (than an average oil) in your opinion? or do you still put them under "no genuine gain" category?

Thanks
 
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if I understand you correctly, sounds like 0W40 oil formulation is much more complex and as a result more potential for things to go wrong.

some of the Euro 0W40 oil have bunch of fancy approvals e.g. MB 229.3/229.5, Porsche A40, VW 502 00/503 01/505 00, Fiat, API SN, etc.

Let's say if someone is looking for a high hths or high viscosity oil for towing and not considering the price and complexity, would the long list of approvals and certs make them more legit (than an average oil) in your opinion? or do you still put them under "no genuine gain" category?

Thanks

I'm sure the Euro 0W40 oils are excellent oils for towing. They will very likely be primarily PAO based & relatively expensive to produce but if your wallet can stand it, why not?

The questions I'd ask myself first would be do I Iive somewhere where I'd definitely benefit from a 0W rating? If not could I live with a 5W40, 10W40 or 15W40 instead because if I could, it would lessen the VII loading with all benefits that would follow on from that. I wouldn't worry about these oils 'taking the heat' worse than PAO. All oils are routinely run in lengthy tests where the bulk oil is maintained at 150°C which is probably the worst temperature you'd see towing.
 
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I'm sure the Euro 0W40 oils are excellent oils for towing. They will very likely be primarily PAO based & relatively expensive to produce but if your wallet can stand it, why not?

The questions I'd ask myself first would be do I Iive somewhere where I'd definitely benefit from a 0W rating? If not could I live with a 5W40, 10W40 or 15W40 instead because if I could, it would lessen the VII loading with all benefits that would follow on from that. I wouldn't worry about these oils 'taking the heat' worse than PAO. All oils are routinely run in lengthy tests where the bulk oil is maintained at 150°C which is probably the worst temperature you'd see towing.

Good point and thanks for the response. 10W40/30 or even 15W40 may be a good idea since all of my towing is in the summer months. I already use lots of 10W30 in the winter or summer due to their lower vii and Noack ...

For some reason (pao?) it's much easier to find 0W oils with fancy certs and approval lists. That's the only reason I was attracted to them.
 

skrypj

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Good point and thanks for the response. 10W40/30 or even 15W40 may be a good idea since all of my towing is in the summer months. I already use lots of 10W30 in the winter or summer due to their lower vii and Noack ...

For some reason (pao?) it's much easier to find 0W oils with fancy certs and approval lists. That's the only reason I was attracted to them.

I am liking where this conversation is going.
 

SR5

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I'm sure the Euro 0W40 oils are excellent oils for towing. They will very likely be primarily PAO based & relatively expensive to produce but if your wallet can stand it, why not?

The questions I'd ask myself first would be do I Iive somewhere where I'd definitely benefit from a 0W rating? If not could I live with a 5W40, 10W40 or 15W40 instead because if I could, it would lessen the VII loading with all benefits that would follow on from that. I wouldn't worry about these oils 'taking the heat' worse than PAO. All oils are routinely run in lengthy tests where the bulk oil is maintained at 150°C which is probably the worst temperature you'd see towing.
All good if you can find a 10W40 PAO synthetic, but I can't.

What if your options were
0W40 in a PAO base
5W40 in a Group III base
10W40 in a Group II + Group III semi-synthetic
15W40 in a Group III conventional

That's mostly what is around here
 
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All good if you can find a 10W40 PAO synthetic, but I can't.

What if your options were
0W40 in a PAO base
5W40 in a Group III base
10W40 in a Group II + Group III semi-synthetic
15W40 in a Group III conventional

That's mostly what is around here

Yes, that's all very true. There's no technical reason why you can't have a 10W40 full PAO (or even a full PAO 20W50!) oil but they they generally don't exist.

I vaguely recall asking Castrol this question once. The answer I got was that they deliberately try to avoid over-speccing mid-tier oils in order to push consumers towards the expensive (& more profitable) top-tier oils. The marketing philosophy is one of 'adequate-better-best' where segmented consumers can be nudged up the cascade.

I suspect this is compounded within the oil companies themselves with a institution bias against PAO. Yes everyone can agree it's technically good but at four-to-five times the cost of oil derived base oils (which technically aren't that far behind) it's something to use only when you have no other alternative. I sometimes wonder just how much this bias against PAO influenced Shell's drive to GTL?
 
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@Sonofsonof

How much of not having a full pao 10W40 or 20W50 has to do with the requirements that any engine oil has to be labeled with the min W requirements that they meet?
iirc, if an oil can pass a 0W spec/test, then it can not be labeled 5 or 10W ...
can a full pao or pao be formulated to be a 10, 15 or 20W? Aren't PAOs inherently or naturally geared towards passing the 0W requirements?
 
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@Sonofsonof

How much of not having a full pao 10W40 or 20W50 has to do with the requirements that any engine oil has to be labeled with the min W requirements that they meet?
iirc, if an oil can pass a 0W spec/test, then it can not be labeled 5 or 10W ...
can a full pao or pao be formulated to be a 10, 15 or 20W? Aren't PAOs inherently or naturally geared towards passing the 0W requirements?

Okay, a little bit of a complicated answer here. Sorry!

Group I & II base oils come in light, heavy & very heavy varieties & are primarily good for 15W40s & 20W50s. You can make 5W30s, 10W30s & 10W40s with them but only if you're prepared to accept very high Noack.

Group IIIs (& I believe GTL) only come in light varieties (typically 4 to 6 cst). You can make narrow 0W-xx grades & wider 5W-xx grades with them which importantly have lower Noack. You definitely CAN'T make 15W40s & 20W50s from them. Given that the bulk of commercial synthetic oils are Group III based, going synthetic inevitably means a shift to thinner oils.

PAOs come in light, heavy & ultra heavy varieties. The most common varieties are 4 & 6 cst & these find most favour in 0W-xx top-tier oils where they have a small but significant advantage over Group IIIs. However you could conceptually make a full PAO 20W50 from PAO 10 & PAO 40. It would probably be a VII-free mono grade with a zero Noack!! It's commercially reality that rules out such oils rather than any technical reason.

Does that answer you question?
 
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I suppose Redline is about the only one offering PAO oils in the higher viscosity grades, and the higher cost of base oils is reflected in the price of the products.
 
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Okay, a little bit of a complicated answer here. Sorry!

Group I & II base oils come in light, heavy & very heavy varieties & are primarily good for 15W40s & 20W50s. You can make 5W30s, 10W30s & 10W40s with them but only if you're prepared to accept very high Noack.

Group IIIs (& I believe GTL) only come in light varieties (typically 4 to 6 cst). You can make narrow 0W-xx grades & wider 5W-xx grades with them which importantly have lower Noack. You definitely CAN'T make 15W40s & 20W50s from them. Given that the bulk of commercial synthetic oils are Group III based, going synthetic inevitably means a shift to thinner oils.

PAOs come in light, heavy & ultra heavy varieties. The most common varieties are 4 & 6 cst & these find most favour in 0W-xx top-tier oils where they have a small but significant advantage over Group IIIs. However you could conceptually make a full PAO 20W50 from PAO 10 & PAO 40. It would probably be a VII-free mono grade with a zero Noack!! It's commercially reality that rules out such oils rather than any technical reason.

Does that answer you question?

Yes, thank you!

My question was in regards to your post #52. I was curious if not having a full(?) pao 10W40 or 20W50 was because of marketing, supply and demand, etc. or if there were also formulation limitations?
For example, if you had to take a very good base oil that can naturally pass 0W requirements and turn it into for a lack of better word an "inferior" 20W oil ... and you answered my question.
 
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